I was recently looking as we are going in May.
Continental had the lowest fare of $178 RT, but I passed that over to go with Jet Blue. That's because with Continental, we would have had to pay the checked bag fee of $23 each for 2 of us, each way, so that would have added almost $100. If you are not checking any luggage, then that would be the cheapest option and they have many flight times to choose from.
But I went with JB because of the "no charge for the 1st checked bag" policy. Plus we really like JB. It is our favorite with Continental a close second. Depending on when you are going, many of the JB flights are $89 one way, making it $178 RT also.
Also, depending how "north" in NJ you are, you could look at Stewart Intl airport in Newburgh, NY (SWF). JB flies out of there also, but only has one or two flights per day. We would have gone out of there, but preferred the flight times we got out of Newark.